Re: Sweden nuke thread vs. Mercury in coal airborne impacts

["ruth_weiner" <ruth_weiner@email.msn.com>]

Can't quite agree with your calculation.  The particulate emission factor
for coal is 16A lb of particulates per ton of coal burned, where A is the
%ash.  So a completely uncontrolled coal plant would emit 160 lb of ash per
ton of coal.  If the Hg is 1 ppm by weight, and the coal is 10% ash, and
assuming all the Hg in ash goes into fly ash -- a bad assumption -- the Hg
emitted would be

6E6 tons coal/yr * 160 lb ash/ton coal * 1E-6 lb Hg/lb ash = 960 lb Hg/year

or about half a ton.  Now, since uranium (that I happen to know about)
partitions 75% in bottom ash, 25% in fly ash, I would assume conservatively
that mercury would at least partition 50/50, so an uncontrolled plant would
emit about 1 quarter ton per year.  In the U. S., 90% particulate control is
common, and many plants achieve 98%, and I find it hard to believe that
Sweden doesn't control ash emission at all.  So if you have 90% control,
that would give an emission of about 48 pounds of mercury a year.  Given the
usual stack height of coal plants, this would  be diluted by a factor of
about 10,000 before it gets to ground level.

These are textbook calculations (my reference is Wark and Warner).

Ruth Weiner
ruth_weiner@msn.com
-----Original Message-----
From: RadiumProj@cs.com <RadiumProj@cs.com>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Tuesday, August 08, 2000 7:31 AM
Subject: Re: Sweden nuke thread vs. Mercury in coal airborne impacts



>Hg releases today into the environment. A single 1000 MWe coal plant
burning
>6 million tons of coal a year will release 6 tons of mercury into the air
at
>1 ppm of mercury in coal.
>




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